This guide is specifically for SQL Server syntax.
SQL Query to Calculate Date Difference
Calculate the difference between two dates in days, months, or years.
Quick Answer
SELECT DATEDIFF(end_date, start_date) FROM table;
Explanation
DATEDIFF calculates the difference between dates. Syntax varies by database. MySQL uses DATEDIFF(date1, date2), SQL Server uses DATEDIFF(unit, date1, date2).
Query Variants
Mysql Days
SELECT DATEDIFF(end_date, start_date) as days FROM projects;
Postgres Days
SELECT end_date - start_date as days FROM projects;
Sqlserver
SELECT DATEDIFF(day, start_date, end_date) as days FROM projects;
Months
SELECT TIMESTAMPDIFF(MONTH, start_date, end_date) as months FROM projects;
Pro Tips
- Check your database's date function syntax
- Consider timezone issues
- Use appropriate units (day, month, year)
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SQL Server-Specific Notes
This page covers SQL Server syntax. Other databases may have different syntax for similar operations.